1. Field of the Invention
The present invention relates to a vertical recording magnetic head and a method of manufacturing the same, in which a vertical magnetic field is applied to a recording medium to perform a recording operation.
2. Description of the Related Art
A magnetic head apparatus includes a longitudinal recording (or in-plane recording) type in which a magnetic field parallel to the plane of a recording medium is applied to perform a recording operation, and a vertical recording type in which a magnetic field perpendicular to the plane of the recording medium is applied to perform a recording operation. Further, the vertical recording type becomes influential for higher recording density.
A vertical recording magnetic head has a structure in which a sub-magnetic pole layer and a main magnetic pole layer (single magnetic pole layer) are stacked on a surface opposite to a recording medium with a non-magnetic insulating layer interposed therebetween, as well known. The sub-magnetic pole layer and the main magnetic pole layer are magnetically connected at a deep side of a height direction. A coil layer, which is formed about a connecting portion for connecting the sub-magnetic pole layer and the main magnetic pole layer, exists within the non-magnetic insulating layer. If a recording magnetic field is induced between the sub-magnetic pole layer and the single magnetic pole layer by applying a power to the coil layer, a leakage magnetic field generated between lateral end portions of the opposite side of the recording medium of both the magnetic pole layers passes through a hard film of the recording medium in a perpendicular manner, and then returns through a soft film. The leakage magnetic field is concentrated on a cross section of the single magnetic pole layer having a small area. Thus, a magnetic recording is performed on a part opposite to the main magnetic pole layer.
In such a vertical recording magnetic head, a neck height position (height direction dimension) of the main magnetic pole layer becomes one factors to decide the recording characteristic. If the neck height position of the main magnetic pole layer is too low, the leakage magnetic field increases, and a track width thus increases. In contrast, if the neck height position of the main magnetic pole layer is too high, the leakage magnetic field becomes difficult to reach the recording medium, and recording efficiency is thus lowered. For this reason, it is necessary to control the neck height position of the main magnetic pole layer in an optimal manner.
Further, the magnetic head apparatus includes a vertical recording magnetic head apparatus of a combination type in which a vertical recording magnetic head is formed on a read element that reads information of the recording medium. In this combination type, the neck height of the main magnetic pole layer was conventionally decided on the basis of the height of the read element. That is, the height of the read element is decided by polishing one cross section that becomes the surface opposite to the recording medium while detecting a resistance value of the read element, which varies depending upon the area of the element, and finishing the polishing process when the resistance value of the read element reaches a predetermined value. The neck height position of the main magnetic pole layer is decided based on the position of the surface opposite to the recording medium. Japanese Unexamined Patent Application Publication Nos. 1985-177416, 1989-169713, 1990-49212, 1992-78013 and 2000-195020 are examples of the related art.
However, if polishing of the surface opposite to the recording medium is finished when the resistance value of the read element reaches a predetermined value, the height of the read element in each vertical recording magnetic head apparatus becomes constant. There is, however, a possibility that the neck height position of the main magnetic pole layer may become irregular and thus have deviation. As described above, if the neck height position of the main magnetic pole layer is short of a predetermined range, a desired recording characteristic cannot be obtained. Furthermore, since the main magnetic pole layer exposed onto the surface opposite to the recording medium is very small, it is difficult to view the neck height position.